The specific aims of the proposal are (1) a C. jejuni cadF mutant will be generated by homologous recombination; (2) C. jejuni binding deficient mutants will be isolated by testing M-methyl-N'-nitro-N-nitrosoguanidine and ultra violet-irradiated bacteria in binding assays; (3) C. jejuni insertional knockout mutants will be created in genes of interest using allelic exchange mutagenesis; (4) C. jejuni insertional mutants deficient in their ability to enter INT 407 epithelial cells will be tested for their in vivo pathogenic behavior using a newborn piglet model.